The invention relates to a rack according to the preamble of claim 1.
A rack of this type is known from European patent specification EP 0 686 817. This patent specification discloses in FIG. 1A an embodiment of a rack which is made up of at least two uprights and shelves which are placed between the uprights and rest thereupon. The uprights each comprise, in this case, two upright elements which are connected close to the top and bottom ends. The shelves comprise two girder elements which extend between two upright elements forming part of separate uprights.
The rack is constructed by fastening two couplers by means of clamp connections to two mutually opposing upright elements. Following placement of these couplers, the girder element can be placed between them, which girder element is clamped to the couplers by means of a wedge-shaped connection. A stable rack is thus obtained without the use of secondary connecting elements such as bolts and the like.
The good quality of the clamping connection between the upright elements and the couplers is attributable to the combined effect of a coupling cam and a coupling rib on the upright element, which cooperate with respectively a cam-receiving groove and a rib-receiving groove located on two separate sides of the coupler. One or more walls of the cam-receiving groove in the coupled state act as a cam-supporting wall. Following coupling to the upright element, the coupler rests by means of the cam-supporting wall on the coupling cam of the upright element. At the same time, the coupling cam and the cam-receiving groove ensure that the coupler clamps against the upright element, by virtue of the fact that one internal wall of the cam-receiving groove and one wall of the coupling cam stand obliquely relative to the vertical. The coupling rib, in combination with the rib-receiving groove, limits the freedom of motion in the horizontal direction.
A disadvantage with the clamping connection of this known rack is that a coupler has to be fitted to the coupling rib and coupling cam by means of a rotary motion about a vertical axis at the site of the coupling rib. It will be clear that this rotary motion can only be performed on one upright element at a time and that at least one coupler must therefore be loose from the girder element in order to effect a connection. In practice, in many cases even both couplers will be released, because it is impossible or impractical to co-rotate the girder element with the coupler during coupling. A relatively large number of loose components, as well as a relatively large number of operations, are therefore necessary to assemble a rack.
A second disadvantage of this known rack is that the upright element can be made only by pressing or die-casting in dies of a certain length.